Coaxial cable is commonly used by the cable telecommunications industry to carry high frequency broadband signals. Coaxial cable or “coax” generally comprises a round central primary core conductor surrounded circumferentially by a dielectric insulating layer that is in turn surrounded by a cylindrical ground conductor braid that is surrounded by an additional dielectric insulating layer.
To ensure proper coax connections that minimize signal loss and provide impedance matching, the cable industry has developed standard coaxial cable connectors, commonly referred to as RF connectors that fit the inner conductor, dielectric, and jacket dimensions of coaxial cable. These RF connectors generally comprise a male connector part that is typically applied to a coaxial cable and a female connector part that is typically connected to a coax device or splice; the male and female connector parts being adapted for engagement with each other. Examples of standard RF connectors include F, BNC, and N connectors, to name a few. Adapters have also been developed for connecting one type of standard RF connector with another, such as for connecting an F connector and a BNC connector. Accordingly, cable telecommunications equipment is typically manufactured with RF connector compatible ports. For example, a typical set top box or cable-ready television found in a subscriber's home may be provided with a female F connector port so that it can be readily connected to a male F connector at the end of a coax drop cable.
Although coaxial cable is capable of carrying power in addition to RF signals, power is typically only provided to coaxial cable on the transmission side of a cable network and is not provided to the subscriber. In the past there has been little need to provide an interface between an RF connector and a standard dc power connector as most coaxial devices in the home that required power were provided either with a plug or a dc power jack. For example, a cable-ready television is typically provided with an RF connector port to receive RF signals via a coaxial drop cable and a plug that can be plugged directly into a wall outlet for power. Most cable modems are provided with an RF connector port for receiving signals from a coax drop cable and a dc jack that is adapted for connection with a barrel plug connector of a dc power adapter that is plugged into a wall outlet. With the development of new technology, however, it is becoming increasingly desirable to provide power to cable industry devices both at the transmission network and at a subscriber's home that are not provided with a dc jack or a plug but only with RF connector ports. For example, it may be desirable to provide power to a line extender in the network or to a drop amp in a subscriber's home that has RF connector ports. Drop amps have become particularly common as subscriber's increase the number of devices which receive the cable signals, thereby necessitating a boost in the RF signals.
But whereas the cable telecommunications industry made its devices compatible with RF connectors, power supplies are typically provided with connectors that are not compatible with RF connectors. For example, the typical dc power adapter that plugs into a standard wall outlet is provided with a barrel-type connector arrangement in which a male barrel plug is adapted for engagement with a female jack. Standard barrel connector sizes have been developed by various companies and standard setting bodies and these connectors are typically classified by the barrel diameter of the plug and the pin size of the female jack. Because of this incompatibility between RF connectors and dc power connectors it is often difficult and time consuming to provide a power connection to a coaxial device.
Presently, one method of providing power to an RF connector compatible device on the cable network is through the use of external leads that connect to pigtails of a power supply. For example, external leads are provided to a coax device and the dc barrel connector of a power adapter is replaced with pigtails. The leads are then soldered to the pigtails to provide an electrical connection between the coax device and the power adapter. Another method is through the use of an F connector provided with an external lead. The F connector is connected to an RF port of a coax device and the lead attached to the power circuit of a printed circuit board. These prior art arrangements have several drawbacks, however. First, the arrangements require the customization of the coax device and/or the power supply. In addition, these arrangements are difficult to install and the resulting connections have a large number of interfaces which increases the chance of breakdown and power loss. Furthermore, once connected these prior art arrangements are also not easily disconnected when desired. Finally, such arrangements raise various regulatory issues, particularly with regard to the power supply.
From the foregoing, it can be appreciated that it would be desirable to have a better approach for providing power to a coaxial device and more particularly, for providing an interface between a standard RF connector and a standard dc power connector.